The present invention relates to a contact for PGA and a PGA socket for connecting a PGA (Pin Grid Array) package provided with a plurality of pins in a grid array fashion to a circuit board substrate and the like.
A PGA socket includes a base housing formed with contact holes in a grid array fashion, a plurality of contacts located in the contact holes, a cover housing formed with through holes in a grid array fashion which the pins of the PGA package can be inserted through, and a sliding mechanism for sliding the cover housing over the base housing. Each contact includes a press-fitting portion for press-fitting the contact to be engaged to the base housing, a contact portion for being in contact with a pin of the PGA package, and a soldering portion for soldering the contact to a printed circuit board and the like. By soldering a plurality of contacts on a printed circuit board and the like, the PGA socket is mounted thereon.
The pins of the PGA package are inserted into the PGA socket through the trough holes of the cover housing by zero insertion force to a position in which the pins of the PGA package face the contact portions of the contacts. The cover housing is slid over the base housing by the sliding mechanism of the PGA socket and then the pins of the PGA package come in contact with the contact portions of the contacts to be electrically connected therewith. Signals can be thereby transmitted between the PGA package and the printed circuit board and the like.
However, upon soldering the soldering portions of the contacts on the printed circuit board and the like, flux may go into the PGA socket from the soldering portions through the gap between the contacts and the base housing to adhere on the contact portions of the contacts. In such a case, even if the pins of the PGA package and the contacts are contacted, a loose electrical connection is arisen that the pins and the contacts are not electrically connected. For this reason, yield of products containing PGA sockets, printed circuit boards, etc. has been decreased.
It is an object of the present invention to provide a construction of a contact for PGA that prevents a loose electrical connection caused by flux adhering on a contact portion of the contact and increases the yield of the products and to provide a PGA socket including contacts of the construction.
A contact for PGA of the present invention formed by bending a metal plate comprises a plate-like base portion, a projecting portion provided continuously in the base portion to extend in a direction substantially equal to the base portion, a turned portion provided continuously at one end of the base portion to face the base portion, and a tail portion provided continuously at the other end of the base portion not to face the base portion.
According to the contact for PGA, where the turned portion is used as a contact portion of the contact and a surface of the turned portion not facing the base portion is used as a contact surface for being in contact with a pin of a PGA package, even when the tail portion is soldered on a board and the like, a frequency of adhesion of flux is lowered to a great extent since flux may usually move between the base portion and a surface of the turned portion facing the base portion. For this reason, when the above-mentioned contact is used for a PGA socket, a loose electrical connection of the pins and the contacts can be prevented, resulting in increase in yield of the products. The contact for PGA may be manufactured at low cost since the contact may be obtained by bending the metal plate.
PGA sockets include PGA sockets used in desktop personal computers, micro PGA sockets used in notebook type personal computers and the like.
The above-mentioned contact for PGA further includes a pair of facing portions provided continuously in the turned portion to extend in a direction substantially perpendicular to a direction connecting between the one end of the base portion and the other end of the base portion add to face each other. According to the contact for PGA, when a pair of facing portions is used as contact portions, a pin of a PGA package and the contact are electrically connected more reliably, since the contact and the pin are to be in contact at two points.
A PGA socket of the present invention comprises the above-mentioned contacts for PGA, a base housing formed with a large number of contact holes for holding the contacts by a press-fit of the projecting portion in a grid array fashion, a cover housing located to overlap the base housing and formed with a large number of through holes in a grid array fashion through which the pins of the PGA package for being electrically connected with the contacts for PGA can be inserted, and a sliding mechanism for sliding the cover housing over the base housing.
According to the PGA socket, each contact used therein has a construction where flux is difficult to adhere on the contact portion for being in contact with the pin of a PGA package. Therefore, a loose electrical connection caused by flux adhering on the contact portion is not likely to occur, resulting in increase in yield of the products.